<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html lang="en">
<head>
	<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
	<title>demo10</title>
	<style type="text/css">
		div{
			float: left;
			border:1px solid blue;
			width: 300px;
			height: 300px;
		}
		div.a{
			height: 600px;
			width: 900px;
		}
		div.b{
			width: 500px;
		}
	</style>
</head>
<body>
<div class="a">a</div><div class="b">b</div><div class="c">c</div>
</body>
</html>